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  • Vision therapy

    serch.it?q=Vision-therapy

    Vision therapy (also known as vision training, or VT) is used to improve vision skills such as eye movement control, eye coordination, contrast sensitivity, and perception. It primarily focuses on improving visual skills in amblyopia and many binocular vision anomalies including accommodative disorders, vergence disorders, eye movement disorders, and the training of stereopsis. VT involves a series of procedures carried out in both home and office settings, usually under professional supervision by an Optometrist. Orthoptics is a similar discipline, but primarily involves exercises which work on eye alignment for patients with strabismus. Many strabismic surgeons have an orthoptist in-house. Vision therapy can be prescribed when a comprehensive eye examination indicates that it is an appropriate treatment option. The specific program of therapy is based on the results of standardized tests and the person's signs and symptoms. Programs typically involve eye exercises and the use of lenses, prisms, filters, occluders, specialized instruments, and computer programs. The course of therapy may last weeks to several years, with intermittent monitoring by the eye doctor.

  • Bird vision

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    With forward-facing eyes, the bald eagle has a wide field of binocular vision.Vision is the most important sense for birds, since good eyesight is essential for safe flight, and this group has a number of adaptations which give visual acuity superior to that of other vertebrate groups; a pigeon has been described as "two eyes with wings". The avian eye resembles that of a reptile, with ciliary muscles that can change the shape of the lens rapidly and to a greater extent than in the mammals. Birds have the largest eyes relative to their size in the animal kingdom, and movement is consequently limited within the eye's bony socket. In addition to the two eyelids usually found in vertebrates, it is protected by a third transparent movable membrane. The eye's internal anatomy is similar to that of other vertebrates, but has a structure, the pecten oculi, unique to birds. Some bird groups have specific modifications to their visual system linked to their way of life. Birds of prey have a very high density of receptors and other adaptations that maximise visual acuity. The placement of their eyes gives them good binocular vision enabling accurate judgement of distances.

  • Presbyopia

    serch.it?q=Presbyopia

    Presbyopia is a condition associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Symptoms include difficulty reading small print, having to hold reading material farther away, headaches, and eyestrain. Different people will have different degrees of problems. Other types of refractive errors may exist at the same time as presbyopia. Presbyopia is a natural part of the aging process. It is due to hardening of the lens of the eye causing the eye to focus light behind rather than on the retina when looking at close objects. It is a type of refractive error along with nearsightedness, farsightedness, and astigmatism. Diagnosis is by an eye examination. Treatment is typically with eye glasses. The eyeglasses used have higher focusing power in the lower portion of the lens. Off the shelf reading glasses may be sufficient for some. People over 35 are at risk for developing presbyopia and all people become affected to some degree. The condition was mentioned as early as the writings of Aristotle in the 4th century BC. Glass lenses first came into use for the problem in the late 13th century.

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